A further 452 jobs are being lost as a result of the collapse of construction giant Carillion.
The Official Receiver said the jobs cover a variety of roles connected with private and public contracts across the country, as well as back office functions.
The losses are on top of 377 announced on Friday.
A further 100 jobs linked to public sector contracts have been safeguarded, said a statement, adding: “We appreciate this will be a difficult time for those who have lost their jobs.
“Jobcentre Plus’ Rapid Response Service stands ready to support any of these employees by providing advice and information so people can move into a new job as quickly as possible. People who have been made redundant will also be entitled to make a claim for statutory redundancy payments.
“Our efforts are focused on the smooth transfer of Carillion’s contracts to new providers and we will continue to keep Carillion’s workforce updated as these arrangements are finalised.”
Shadow business secretary Rebecca Long-Bailey said: “The Government has let down workers and businesses impacted by Carillion’s collapse.
“Eight hundred workers have lost their jobs, more are left not knowing what the future holds for them, and Carillion’s shoddy treatment of businesses in its supply chain threatens even more jobs.
“The Tories have failed to protect the pay, conditions or pensions of workers on Carillion contracts. They must act now act quickly to ensure that these workers receive swift redundancy payments and are properly supported.”